In the autumn of 2017, about 250 walruses in Russia, having climbed up to rocky slopes overlooking a beach, just walked over the edge.
Usually, gravity is no enemy of the walrus. When these animals encounter hard surfaces, they rise up to meet them, hauling their two-ton bulks onto floating pieces of ice. When they fall, they flop off those low platforms into the accommodating water. So you might imagine that a walrus, peering off a tall cliff, doesn’t really understand what will happen to it when it steps off. It doesn’t expect to plummet for 260 feet, cartwheel through the air, bounce off the rocks, and crash abruptly. Climb, plummet, cartwheel, bounce: These are not walrus-associated verbs.
Nor is landing. The biologist J. B. S. Haldane once wrote a famous essay in which he described what large falls do to progressively larger animals. A mouse “gets a slight shock and walks away,” he wrote. “A rat is killed, a man is broken, a horse splashes.” And a walrus? “Many just die on impact, or they crush the ones they fall on below. Some have internal injuries, get to the sea, and wash up later,” says Sophie Lanfear, who led a documentary crew that recorded the behavior for Our Planet—Netflix’s big-budget answer to Planet Earth. The team had heard hints about such falls, but were still unprepared for the shock of seeing them. “It’s the worst thing I’ve ever filmed,” says Jamie McPherson, a cameraman, on a behind-the-scenes video.
Our Planet makes a point of saying what other nature series have not—the wonders they’re showing are endangered because of humans—and the footage is perhaps the most shocking part of a series full of discomfiting moments. Contrary to popular belief, not even lemmings dive off cliffs. Why would a walrus? Polar bears weren’t harassing them. The camera crews were filming from afar so their scents and sounds wouldn’t spook the skittish animals. Then why? What were walruses even doing on cliff tops in the first place? Our Planet offers a clear answer. “This is the sad reality of climate change,” Lanfear told me. “They’d be on the ice if they could.”
In the summer, Pacific walruses forage for shellfish in the waters between Alaska and Russia, before hauling up onto sea ice to rest and raise their young. But in recent years, Arctic sea ice has been thinner and sparser. The 2017–18 season marked a record low. As these icy platforms have retreated, walruses have increasingly been forced to haul out onto solid land—in the thousands.
These haul-outs aren’t new events, but they were once rarer, smaller, and less dangerous, according to Anatoly Kochnev, a Russian naturalist who has studied walruses for 36 years. When he started, only males gathered on these sites; now females and calves do too, and many are trampled in the scrum. When he started, haul-outs were rare in the northerly Chukchi Sea; now many sites there regularly heave with walruses.
With Kochnev’s help, the seven-person Our Planet team filmed one of the largest haul-out sites—a single beach where 100,000 walruses tessellate into a solid red mat of tusks and blubber. The animals arrived almost overnight, while the team slept in a cramped hut. “It was like 100,000 Chewbaccas outside,” says Lanfear. “We could hear tusks scraping along the side of the walls. We could hear walruses snoring. We opened the door, and it was a wall of blubber.” The walruses gather “out of desperation, not out of choice,” David Attenborough says over the resulting footage. “A stampede can occur out of nowhere. Under these conditions, walruses are a danger to themselves.” And so they climb “to find space away from the crowds.”
As the walruses spread across the beach, some start heading up a shallow slope, which curves into a steeper escarpment, which eventually culminates in 260-feet cliffs. It’s not an easy climb, but Kochnev suspects that once one group leads the way, the rest follow their scent. And since this area gets very little rain, odor trails from previous years might lead new arrivals up a dangerous path. “At least up here, there’s space to rest,” Attenborough intones. “A walrus’s eyesight out of water is poor, but they can sense the others down below. As they get hungry, they need to return to the sea. In their desperation to do so, hundreds fall from heights they should never have scaled.”
Our Planet draws a straight line between climate change, sea-ice loss, bigger haul-outs, overcrowding, climbing walruses, and falling walruses. “It is not a normal event,” says Lanfear. “It’s such a tangible, obvious thing to show people. It’s clear as day.”
But a few walrus scientists who saw the clip have questioned parts of this narrative—including the claim that walruses are climbing “to find space away from the crowds.” “Walruses thrive on crowds and haul out in tight groups, even when space is available,” says Lori Quakenbush from the Alaska Department of Fish and Game. Also, in the sequence, it looks as if the beach beneath the teetering walruses is relatively empty. What crowds are they escaping from?
This confusion arises from the ways in which documentaries elide space and time. Lanfear clarifies that the sequence includes footage from two separate beaches—one with the 100,000-strong congregation and one with the falls. At the latter, walruses started climbing only once the area beneath the cliffs had completely filled up; gregarious or not, they had no room. Once at the top, they rested for a few days, and walked off only after the beaches below had emptied. Indeed, as the narration suggests, the sounds of their departing comrades may have lured the cliff-top walruses off the edge. “They seemed to all want to return to the sea to feed as a group,” Lanfear says.
Quakenbush and others also doubt that the climbs and falls are related to climate change, because such tragedies have been reported since before sea ice showed substantial declines. “Walruses have shown similar behavior on the U.S. coastline when space and ice were not an issue, and the reason is unknown,” says Lori Polasek from the University of Alaska Fairbanks. For example, in three successive years, from 1994 to 1996, dozens of male walruses fell to their death from cliffs in southwestern Alaska. But Kochnev and Lanfear argue that the incident captured in Our Planet is exceptional in both the height of the cliffs and the number of walruses that plummeted and died—hundreds as opposed to dozens.
The reason for the falls might be complicated, but it’s clear that climate change is affecting the walruses. “We do believe that haul-outs have increased in size due to the loss of sea ice—in part, due to females and their calves moving to land during summer,” says Nicole Misarti from the University of Alaska Fairbanks.
These changes have affected the indigenous communities that have traditionally hunted, protected, and lived alongside walruses. The 200 Chukchi people who live in the Russian village of Vankarem are familiar with local haul-outs. But according to one resident, Vladilen Ivanovich Kavry, the gatherings have become more crowded, and the walruses look weaker. They’re edging closer to the village, and those killed during stampedes attract polar bears, which are also coming ashore because of the vanishing sea ice.
The community have since set up a patrol to watch for incoming bears and tow walrus carcasses to far-off sites. They’ve also worked with the local aviation service to restrict flights over haul-out sites, to avoid spooking the walruses. And they’ve shared their expertise with their counterparts in Alaska. “In the spring of 2010, we invited Chukchi colleagues to travel to Alaskan villages to talk about their work in protecting polar bears and walruses,” says Margaret Williams, who directs the World Wildlife Fund’s Arctic Program. “They said, ‘Soon our walruses will come to you.’”
That spring, tens of thousands of walruses appeared at Point Lay, Alaska. Such haul-outs were once rare; now they’re an annual fixture, which the U.S. Fish and Wildlife Service says is “most likely” connected to global warming. Walruses, it seems, can no more resist the changing of the world than they can defy gravity.